


Trust is a Virtue

by Flamefriends



Category: Undertale (Video Game)
Genre: Denial, Dubious Consent, FUSW, Grillby is a vampire, Injury, M/M, Pain, Soul Sex, mention of past injury/illness, sansby - Freeform
Language: English
Status: Completed
Published: 2020-10-05
Updated: 2020-10-05
Packaged: 2021-03-08 04:42:05
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,654
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26819722
Author URL: https://archiveofourown.org/users/Flamefriends/pseuds/Flamefriends
Summary: Sans and Grillby have a date in Waterfall, but not the kind you're probably thinking of. Sans is equal parts excited and dreading their little get together, but why? Grillby's nothing to be afraid of, right?
Relationships: Grillby/Sans (Undertale)
Comments: 2
Kudos: 20





	Trust is a Virtue

**Author's Note:**

> So generally when people do fusw they make several pieces over the course of the time limit. I, however, only managed to find the time to write one. Nevertheless, I managed to incorporate all of the prompts from this year into this one piece, so I hope it balances out some. Let me know if I missed any tags. It' been a while.

“SANS! GRILLBY IS AT OUR DOOR AGAIN!” 

Sans felt his whole body flinch hearing that name, though whether from anticipation or something else, not even the skeleton knew. He wasn’t ready. There was still more he could do to prepare for this. He was out of time though. He couldn’t keep his date waiting. Taking a deep breath, Sans gave himself a once-over, adjusted his clothes to smooth out a few wrinkles, then headed into the hall.

Reaching the bottom of the stairs, Sans was greeted by the sight of his brother having a somewhat tense conversation with the fiery bartender across the threshold of the front door. Said conversation came to a halt when they noticed Sans’ presence, but the older skeleton could pick up on their cues. Papyrus was worried about him. He didn’t blame him. Hell, last time he’d gotten home and then collapsed on the carpet. Papyrus had to carry him to his bed so he could recover properly, and had chastised Sans the entire time. The familiarity made the older brother smile to himself, even if it did make Papyrus worried sick. Sans wanted to believe that he didn’t mind these side-effects, but as much as he tried to tell himself that everything was fine, there was always that part of him that just wanted it all to stop.

It couldn’t stop though, at least not so easily. They were in too deep. There was too much at stake. He couldn’t just throw everything out because of an inconvenience. He could handle it. That, at least, he was mostly sure of.

“you alright, bro?” Sans gave Papyrus a concerned stare. He was probably the one suffering the most from this situation. Having to watch one’s own kin go through the same destructive cycle every other week no doubt took a toll on one’s mind. Hurting Papyrus was probably the worst part of this whole mess.

“OF... OF COURSE I’M ALRIGHT,” Papyrus responded, somewhat unconvincingly. He stepped away from the door and made an exaggerated attempt to stand up straight and puff out his chest. The show of fake bravado was as comforting as it wasn’t. Of course Papyrus would put on a brave face for him. That’s just the kind of monster he was. “I HOPE YOU TWO HAVE A GOOD TIME. GRILLBY! I WILL EXPECT MY BROTHER HOME IN A TIMELY MANNER. IF HE'S NOT BACK IN A TIMELY MANNER, I WILL TAKE ACTION. PLEASE TAKE THIS INTO CONSIDERATION.”

Grillby’s eyes, two white spots in a sea of orange, crinkled up in a soft smile. The gesture was warm and kind, and it made Sans’ anxiety and dread lessen just a little bit. Stars, Grillby was so beautiful. “I’ll be sure to bring him back on time...” the elemental said. 

Grillby always said that, and Grillby was always on time. Sometimes even earlier on a bad day. Sans hoped today wouldn't be a bad day. He didn't know if Papyrus could take it. "i'll see you when i get home, paps." With one final exchange between the brothers done, Sans stepped over the threshold to meet Grillby properly. Though Papyrus still seemed reluctant, he hid it well, and shut the door behind them. 

"so, uh..." Sans could feel his soul fluttering in his rib cage. He was so anxious, and at the same time he was so excited. Grillby didn't say anything at first. Instead, he offered a hand for Sans to hold. The gesture was a sweet one, and it made the small skeleton's soul sing. He took that warm hand in his own, and again his anxiety ebbed away a little. 

"I made lunch..." With his other hand, Grillby revealed a little box he'd been hiding. No doubt it contained some of the best food Sans could hope for. Anything the elemental made was delicious, so Sans wasn't going to be picky by any stretch of the imagination. 

"thanks, g. can i eat it on the way," Sans asked with a hopeful grin. If he focused on the good, he could force himself to forget about the bad. That's how it worked, right? He was so nervous, he didn’t think he could stomach whatever special treat Grillby had prepared, but he didn’t want to seem ungrateful. Luckily, the elemental nodded, and handed Sans the box. One look inside told Sans all he needed to know: he’d finish before they reached the halfway point. "you, uh, want to get going then?" Grillby nodded, and the two started walking their way towards Waterfall. 

. . . . . . . . . .

The sounds of water lapping against stone accompanied the sound of footsteps. Sans had taken the lead, carefully guiding his glowing friend through the dryer parts of the cavern. Grillby's fire made the gemstones above glitter so prettily, almost like real stars. It was one of his favorite parts about these walks. Maybe one of these days they'd get to see the real thing. 

Nah. It was a nice thought though. 

"careful." Sans' hold tightened around Grillby's arm when a piece of the thin path they were walking on broke away under the bartender's feet. Both men struggled to keep Grillby's leg dry, and in the end they managed it by the skin of their teeth. 

"We might have to find a new place soon..." Grillby murmured. The erosion of the path was undeniable. Every time they came here, it seemed that more and more of it was falling into the water. They probably would have to find another spot soon, much to Sans' dismay. He loved this spot, but Grillby had a hard enough time walking across the bridge blooms without having a panic attack. He wasn't going to subject him to that kind of torment on top of the torment they already lived in. That just wouldn't be right. 

With a solemn nod of agreement, Sans helped Grillby the rest of the way to their private, little spot. A singular bench sat in a little alcove next to a lonely echo flower. The flower was repeating Grillby's voice, though a little distorted after so much time had passed. “ _ Let’s get you home... _ ” A soft note from the flower, and a reminder of dates passed. 

The moment they reached the bench, Sans melted into the seat with a sigh. All that walking really took it out of him. He heard Grillby snicker as he took his spot next to him, and the echo flower repeated the sound. He just grinned. "what's that for?"

"Sorry... You're just so predictable..." The comment confused Sans, and the flower’s echoing didn’t exactly help, but Grillby didn't give him long to ponder it over. Strong arms came to wrap around Sans' small frame and pull him close to the fiery monster he loved so much. He tensed up for a quick second, but after feeling hot breath and sharp teeth nip at his vertebrae, Sans had to force his soul to relax. They didn't have time for an anxiety spike. "How have you been holding up...? Since last time, I mean..." Grillby spoke softly while his hands wandered along the other's body, trying to slip beneath his clothes and get to the bones hiding inside. 

He hated that they were stuck like this. Such a kind and caring monster didn't deserve to be cursed like this. Sans trusted this monster with his life, and it hurt that something like this was just something they had to deal with. He hated being afraid every time him and Grillby got close. He hated that things couldn't be simple. Why did it have to be him? "oh, you know. a little drained, but nothing i can't handle." He grinned wider, and decided to help Grillby strip him. 

"Sans..." He said it in that familiar tone that couldn't decide if it was a groan or a whine. Sans loved hearing him struggle over his puns in the heat of intimacy, and he especially loved watching Grillby struggle with the flower throwing his voice back in his face. Hands of both bone and fire alike worked together to peel away the layers of clothes holding Sans' bones hostage. Their combined efforts made short work of those material bindings, and soon the small skeleton was free. He sat there, leaning back a little while Grillby loomed over him. The air was cool against his bones, but Grillby's fire protected him from the slight chill.

"grillbs, i'm fine," he lied, the flower soon repeating that lie. His soul was beating so fast and he wasn't sure what the strongest reason for his anticipation was. Fear? Lust? They blended together so easily here. Sans closed his eyes, ignoring the echo flower so he could focus, and soon a soft light started to glow from within his rib cage. He reached a hand inside and cradled the little upside down heart within his palm, only to bring it outside of its cage to present to his date. His soul was pocked with little scars left over from their past dates. A small part of him was proud of them, but it was overshadowed by the part of him that  _ hated _ how ugly it looked. Broken, marred, his soul was so pitiful. "here. you should eat."

Grillby stayed close, his eyes gliding down to find Sans’ little present before taking it from the skeleton. The elemental cradled it gently in his hand, and the warmth of his fire seeped into it to warm Sans’ bones. He liked that warmth, especially now that he had nothing to protect him from the elements. The flower repeated Sans’ invitation, helping guide Grillby to do the thing they came here to do. He brought Sans’ soul to his face, and his mouth split open to reveal sharp, fiery teeth. Hot breath warmed Sans’ soul, and the rest of him by extension. 

Sans had just enough time to brace himself before the sharp, hot pain tore through his entire being. He screamed, and the sound echoed through the space and from the flower. Grillby held him down with one arm, and Sans gripped the other tightly while he fought back tears. Grillby needed his magic more than his sockets did! He felt like he was getting cut in half and burned at the stake at the same time, and yet between his own personal restraint and Grillby physically restraining him, he managed to not squirm too much. This was always the worst part. Soon though, any moment now--

Just when Sans started to wonder how long the pain would last, the sensations changed. He still felt hot, but the invisible knives cutting invisible wounds into his bones let up, only to be replaced by something  _ much  _ better. He was still so warm, but now he felt the ghost of the elemental’s touch reaching all of his most sensitive places. Dazed eye lights glanced at the fire, and a moan tore through this throat when they saw a thumb gently kneading into the sensitive flesh of his marred soul. That golden hand knew just how much pressure to use to make his magic light up like a live wire. 

Sans felt his back almost strain into an arch despite being held down. Only a few little circles in and he was already getting lost in the pleasure. Such was the power of a soul's sensitivity in the hands of someone who knew exactly how to handle it. Sans was all but putty in Grillby's hold. His mind, his body, his magic, his soul -- every part of him belonged to the elemental, and the fire rewarded his devotion with the warmth and pleasure that he craved so much. Eventually, those ministrations brought Sans to the edge, and with one final push of his thumb, all of that pleasure spilled over. Sans was reduced to a dazed, babbling mess, echoed by the flower, as concentrated magic gushed from his abused organ. None of it escaped the elemental, who greedily lapped up every ounce of the sweet soul nectar for himself. 

Distantly Sans felt Grillby's teeth withdraw from his soul, but he was so buzzed from such a powerful orgasm that even if there was pain to be felt, he didn't register it. He gazed up at the ceiling, eye lights fuzzy and unfocused, and took a moment to catch his breath. He felt satisfied, his bones felt warm. His soul beat calmly in Grillby's grasp. 

And then, after one last lick that left Sans’ whole body shivering, Grillby returned his soul to its home inside his rib cage. Sans sighed, and braced himself for the inevitable; the instant those fiery fingers lost contact with his soul, all the warmth in Sans’ body vanished in an instant. It was jarring -- it had knocked the wind out of him the first time -- but he was prepared now. Mostly. He still shivered from such a drastic change in temperature, but he held back any noises of distress for Grillby’s sake. His body felt so cold now...

He laid there for a while, panting lightly while he tried to get his body to move. His joints ached from being so tense, and his entire being felt so cold. Distantly, he felt the only other heat source available shift away. Hazy eye lights tried to focus on him, but he’d moved out of view. Sans could lit his head if he wanted to, but his body wouldn’t cooperate with him. He was just so drained. He closed his sockets, just for a moment... 

Only to awaken from having a pile of clothes dumped on his face. Sans grunted, and grabbed the clothes on his way up to a sitting position. Grillby was standing next to the bench, arms crossed expectantly. Sans chuckled awkwardly. He hadn’t meant to fall asleep on the poor guy. “so, uh, how long was i out?” He looked up at the fiery man with a sheepish gaze, only to break it when he pulled his shirt over his head.

“Long enough for me to dry your clothes...” Grillby replied. Sans figured that meant he’d been asleep for around 10 minutes or so. That wasn’t too bad for him, at least. He still felt drained, but that couldn’t be helped. He’d already eaten Grillby’s lunch. He’d have to refuel when he got home. Maybe Papyrus had made something? “Get dressed... Your brother will want you home soon...” It was a bit hard to tell, but Grillby almost sounded... disappointed. Why? Was it something he’d done? He really hadn’t meant to fall asleep.

Swallowing his worries and forcing a calmer expression, Sans finished redressing himself and stood up from the bench. He stretched, arms high above his head, and his vertebrae popped back into place with an audible cracking sound. Of course, the echo flower repeated the sound. “alright, well, let’s get a  _ futon _ the path back.” Grillby eyed him with that gaze he always had when he couldn’t tell if he’d been thrown a pun or not. It only made Sans grin widely, which in turn made that glare from the elemental all the more hilarious. Grillby simply shook his head and started walking. Sans felt a little off-put, but he didn’t let himself linger on the bad for too long. If he did, he’d end up making himself forget all the good he’d done today. Grillby wouldn’t starve because of him. Grillby had made a delicious lunch just for him. Even with the distance between them while they traversed the crumbling path, Sans knew this was for the best. Nothing could convince himself otherwise. He was sure of it.

  
Distantly, the echo flower’s voice grew fainter and fainter, slowly being overpowered by the soft, much closer sounds of running water lapping at the rocky banks. “ _ let’s get a futon the path back. let’s get a futon the path back. let’s get a futon the path back. let’s get... _ ”


End file.
